Shortlist of 7 Top Legacy Software Modernization Companies in Europe [2027]

ByAbaidullah Shahid

European companies increasingly admit that part of the software they rely on daily has run out of road. In a Lünendonk study co-created with IT service firms including Cognizant and Sopra Steria, 62% of more than 150 decision-makers at midsize and large firms said parts of their business-critical applications need renewal.

Knowing a system has to go is easy. The harder task for your business is proving that the move paid off through faster releases, lower run costs, or fewer incidents. Without measures agreed up front, a finished migration can look like a bill with nothing new to show.

In this guide, you will find 7 of the top legacy software modernization companies in Europe for 2027 and break down how each one works and what it delivers. Also, we’ll cover the benefits modernization brings to a growing business and the KPIs that tell you whether your project is paying off.

TL;DR

  • Lünendonk found that 83% of surveyed firms plan a bigger IT modernization budget in 2026.
  • Only 8% of those firms use advanced AI-based code analysis, which leaves a large gap between AI plans and practice.
  • Modernization pays back through lower running costs, faster releases, tighter security, and simpler integration with new tools.
  • A typical project opens with 4 to 6 weeks of assessment and a pilot module before the wider migration starts.
  • Phased migration keeps the old system running until each module proves itself in production.
  • Decommissioning the legacy platform on a fixed date stops double running costs and closes the project properly.
  • A poor-fit partner can leave your business with 2 systems to maintain and a budget that never stops growing.
  • The list of the top legacy software modernization companies in Europe includes Reenbit, MaibornWolff, PKS Software, codecentric, Miquido, Levi9, Altkom Software.

Research Highlights on Legacy Software Modernization in 2027

Spending on modernization keeps rising across European companies, and recent research shows where your own plans stand against your peers.

Budgets point clearly upward. Lünendonk found that 83% of the 150+ IT and business leaders it surveyed plan a bigger modernization budget in 2026, and nearly 1 in 4 expect a rise of more than 5%. The pipeline behind that money stays long as well: 76% of the same group expect at least 20% of their business-critical core applications to need modernization within 5 years.

Tools lag behind ambition. In that July 2025 study, just 8% of firms used advanced AI-based code analysis, and 22% used AI for documentation. Lünendonk co-created the research with IT service providers including Cognizant and msg, and the gap it shows matters for your partner choice, since few teams have AI built into their modernization work yet.

Company size shapes the starting point. Eurostat data for 2025 shows CRM software at 25% of small EU enterprises against 65% of large ones, while business intelligence tools reached 11% of small firms and 69% of large ones. For a growing business, that gap often means customer and reporting data still sit in spreadsheets and older tools that a modernization has to absorb.

Cloud platforms now carry more than email and file storage. Among EU enterprises that bought cloud services in 2025, 45.5% hosted databases in the cloud and 26.1% used it as a platform to develop, test, or deploy applications, according to Eurostat. If your core data still lives on local servers, those figures show how far the market has already moved.

A modernization partner turns the systems that slow your business into software your team can change, extend, and support for years. The firm you pick sets the pace, the risk, and the support you get after launch. The table maps each firm’s founding year, industry focus, services, and delivery method:

Company Founded Industry Focus Modernization Services Delivery Method
Reenbit 2018 Manufacturing, construction, healthcare, retail, fintech, energy, facility management .NET modernization, cloud-native re-architecture, Azure migration, database migration, front-end modernization Phased delivery after a 1–2 week assessment, with AI agents and CI/CD
MaibornWolff 1989 Energy, insurance, manufacturing, mobility Software Health Check, legacy system replacement, software modernization, software integration Health Check, roadmap, then joint implementation with ensemble programming
PKS Software 1991 Banking, logistics Re-platforming, CA-TELON dismissal, legacy Unix rehosting, legacy software assessment, technical debt management Pre-analysis and PoC, detailed concept, implementation and optimization, coaching and support
codecentric 2004 Insurance, retail, manufacturing Status quo analysis, renovation, architecture migration, rebuild, AI integration Architecture review, then renovation, migration, or rebuild
Miquido 2011 Fintech, healthcare, e-commerce, energy and utilities, travel and hospitality Software audits, cloud migration, UX audits and UI redesign, code refactoring Scoping, workshops, design and development, release, ongoing support
Levi9 2005 Retail, finance and insurance, energy, healthtech, mobility, media Cloud migration, cloud modernization, architecture assessments, microservices Architecture assessment, then delivery through Team as a Service
Altkom Software 2000 Banking, insurance, leasing Application modernization without a rebuild, integration services, audits, application maintenance Consultation, workshop, and offer, followed by agile delivery

1. Reenbit

Reenbit is a top legacy software modernization company in Europe for companies on a steep growth curve, where yesterday’s platform now limits tomorrow’s plans. The AI-powered consultancy and Microsoft Partner runs a team of 100+ engineers, and 88%+ of that team carries Microsoft or Azure certifications. Engagements take the form of a tech partnership, dedicated team, or staff augmentation.

What Modernization Covers

Projects span .NET modernization, cloud-native re-architecture, Azure and database migration, and front-end upgrades from AngularJS to Angular or React. Autonomous AI agents take on repeatable refactoring, and secure RESTful APIs open legacy logic to new applications. An energy-sector client now completes key operations in 3–6 seconds, compared with 30–40 before, and Brands of Scandinavia recorded €400,000 in savings during year one.

Support After Go-Live

DevOps and CI/CD pipelines keep releases flowing once the new platform goes live, and the team stays on for post-launch support. Cloudbooking cut its maintenance effort by 27% and holds a 99.9% sync rate after modernization. ISO 27001:2022 controls and GDPR-compliant practices continue through the support phase for regulated clients.

2. MaibornWolff

MaibornWolff has worked with grown software systems for more than 35 years, with 800 employees, ISO 9001 and ISO 27001 certification, and TISAX. Every engagement starts with a 3-week Software Health Check that runs 5 workshops and ends in a roadmap.

What Modernization Covers

Clients choose between a step-by-step rewrite, full redevelopment, or selective renovation. Agentic Domain Discovery reconstructs business logic from COBOL, AS/400, Delphi, and older Java or .NET code inside an isolated Trusted Zone. For the BMW Group, a team of 25 replaced a production logistics system that had grown over 20 years.

Support After Go-Live

An Emergency Response Unit covers critical legacy systems during conversion, and a dedicated team handles maintenance and further development afterward. Ensemble programming in mixed teams of 2–5 hands off responsibility to client engineers step by step.

3. PKS Software

PKS Software has specialized in legacy technology since 1991 and now belongs to TIMETOACT GROUP. Projects follow 4 steps: pre-analysis with a proof of concept, a detailed concept, implementation and optimization, and coaching and support.

What Modernization Covers

The firm re-platforms mainframe and Adabas/Natural systems to Linux or cloud, retires CA-TELON, and rehosts legacy Unix applications. eXplain 10, the firm’s own product, analyzes COBOL, PL/I, RPG, and Assembler with a controlled LLM context. For KBC, the team analyzed 1,411 program sources and replaced CA-TELON within 12 months after a 3-month PoC.

Support After Go-Live

Coaching and support form the last step of every project. The COBOL Survival Team also maintains and develops IBM i applications, and eXplain generates documentation that stays with the client team.

4. codecentric

codecentric employs 500+ experts across 13 locations and holds ISO 27001 certification and a TISAX assessment. Modernization starts with a status quo analysis, often through the firm’s own LASR architecture review, which runs in a few days.

What Modernization Covers

Work ranges from renovation and architecture migration to a full rebuild, with AI integration where it fits. For DEVK, an 8-person team connected a new rate calculator backend in 7 months, and new vehicle types now take 1–2 sprints. Mainframe and client-server systems both sit within the practice.

Support After Go-Live

Long-term support can include full maintenance, and the team takes over operations on request. Documentation, workshops, and training move knowledge to the client, since the firm’s stated goal is to make the external team redundant.

5. Miquido

Miquido has built software since 2011 and now counts 200+ experts. Legacy modernization projects move through scoping and estimation, workshops, design and development, release, and ongoing support, with scoping that sets both price and schedule.

What Modernization Covers

Services include functional, performance, security, and UX audits, cloud migration to AWS or Google Cloud, UI redesign, and code refactoring. UX audits run as 1, 2, or 3-week programs, and the firm puts typical modernization budgets at $30,000 to $150,000 or more.

Support After Go-Live

Ongoing support covers long-term maintenance, upgrades, and new enhancements. The team prepares project documentation during the workshop phase and manages the handover to the client’s in-house developers.

6. Levi9

Levi9 employs 1,200+ people in 4 countries and holds ISO 27001, ISO 27701, and ISO 9001 certification along with a TISAX assessment. The firm has been an AWS Advanced Tier Partner since 2016 and a Google Cloud Application Modernisation Partner.

What Modernization Covers

Cloud migration and cloud modernization sit alongside architecture assessments, technology reviews, and the move to microservices. One published project took a client’s platform from VMware to OpenStack in 10 weeks.

Support After Go-Live

Delivery continues through Team as a Service, with continuous improvement of the platforms the team built. Microsoft partnership of 19+ years, with Digital and App Innovation and Data and AI designations, backs the Azure side of that work.

7. Altkom Software

Altkom Software works mainly with banks, insurers, and leasing firms, which account for about 80% of the firm’s projects. A team of 200+ experts holds ISO 27001 and ISO 27017 certification.

What Modernization Covers

Application modernization focuses on upgrading existing systems without a full rebuild, together with integration services that connect old and new platforms. Audit services, including cloud and process audits, give clients a clear starting point, and one IT systems audit took 6 weeks.

Support After Go-Live

Application maintenance includes updates and technical support after release. Engagements start with a consultation and a workshop, followed by an offer and agile delivery, and the firm reports 600+ projects for 100+ clients.

Benefits of Legacy Software Modernization for Growing Businesses

A modernized system changes what your team can do each week, from how fast a fix reaches customers to how much the platform costs to run. Finance teams and boards rarely approve a modernization budget on technical arguments alone, so the case has to show gains your business can see and measure within the first year. Consider these 5 benefits when you.

Lower Running Costs

Old platforms cost more each year as licenses rise and fewer people can support them. The savings usually come from 4 places:

  • License consolidation. Moving off proprietary databases and middleware cuts annual fees. Open-source and cloud-native options often replace them at a lower cost.
  • Infrastructure right-sizing. Cloud resources scale with real demand. Your business stops paying for servers sized for peak load all year.
  • Fewer incidents. Stable code and automated monitoring reduce outages. Your support team spends less time on firefighting.
  • Smaller contractor bills. Current stacks draw on a wide talent pool. Rates for rare legacy skills stop setting your budget.

Faster Releases and Product Changes

Speed is often the benefit product teams notice first. These changes usually drive it:

  • Automated testing and CI/CD pipelines replace manual regression passes, so your team can ship small changes every week instead of each quarter.
  • A modular architecture lets separate teams work on billing, orders, or reporting without blocking each other in one shared codebase.
  • Feature flags allow your team to release new functions to a small group of users first and roll back quickly if needed.
  • Clear documentation and readable code shorten onboarding, so new developers contribute within weeks of joining your company.

Stronger Security and Compliance

Unsupported operating systems, frameworks, and libraries stop receiving patches, and each month without fixes widens the gap attackers can use. A modern stack brings current authentication, encryption, and logging, which your auditors expect to see.

Compliance work also gets easier. When personal data sits in fewer, documented stores, requests to export or delete records take minutes, and your team can show regulators who accessed what and when.

Easier Integration With New Tools

New SaaS products, partner platforms, and AI services expect APIs and clean data. Old systems often offer a nightly file export at best, so every new tool needs a custom workaround that someone has to maintain. Modernization replaces those workarounds with standard connections your team can reuse. Your business gains:

  • Open APIs
  • Event-driven updates
  • Single sign-on
  • Shared data models
  • Faster vendor onboarding

Room to Grow Without Rewrites

A system that suits one site or one market tends to break when your business adds the second and third. Modernization gives you an architecture that scales with users, transactions, and locations without another full rebuild.

That headroom matters for planning. Your leadership can open a new branch, enter a new country, or launch a product line knowing the software will keep up, and your IT budget can shift from upkeep to new features.

Timeline of a Typical Legacy Software Modernization Project

Every project runs on its own schedule, yet most follow a similar arc from assessment to switch-off. Knowing the usual timing helps you plan budgets and staff. Let’s walk through the 4 stages.

Stage 1. First 4 to 6 Weeks for Assessment and Planning

The opening weeks decide how the rest of the project goes. Your partner maps the code, data, and integrations, interviews the people who use the system daily, and prices each module. By the end, your team should hold a written plan with scope, sequence, and budget. Expect these outputs:

  • Dependency map
  • Data quality report
  • Modernization path per module
  • Phased roadmap
  • Cost estimate

Stage 2. Months 2 and 3 for a Pilot Module

The pilot moves one module with real users and real data onto the new platform. Teams usually pick a module with clear boundaries and moderate risk, so the pilot proves the approach without putting core revenue at stake.

The pilot also tests how your team and the partner work together. Lessons on tooling, review steps, and data migration feed into the plan before the wider rollout, which is the cheapest moment to change course.

Stage 3. Phased Migration Across Months 4 to 12

The main migration runs module by module, with the old system still serving users. Plan for these activities:

  • Each module moves in its own release, with parallel runs that compare outputs against the legacy system before your team switches traffic.
  • Data migrates in stages, with reconciliation checks after each batch so your finance and operations teams trust the new figures.
  • Integrations with partners and internal tools move to the new APIs one by one, with fallbacks ready if a connection fails.
  • Training runs alongside each release, so your staff learns the new screens before the old ones disappear.

Stage 4. Cutover and Decommissioning in the Final Months

The project ends when the old system goes dark, not when the last module goes live. Close it out with these steps:

  • Final cutover. The last users move to the new platform. Your team keeps a tested rollback plan for the first weeks.
  • Data archiving. Records that regulators require move to a searchable archive. The old system no longer has to run just for reading them.
  • License termination. Old platform contracts end on a fixed date. Your business stops paying for 2 systems.
  • Handover. Documentation, runbooks, and access move to your internal team. Ownership stays clear from day one.

Wrapping Up

Modernization delivers its benefits only when the old system actually switches off. Projects that stall halfway leave a business running the old and new platforms side by side, paying for both, and asking the same people to support them, which wipes out the savings that justified the work.

A wrong partner choice tends to cause exactly that outcome. Vague scope, no plan for data migration, and no fixed decommissioning date leave your team holding a half-finished system and an open-ended bill. The top legacy software modernization companies in Europe plan the switch-off from the first week, so ask each candidate to show you when and how your legacy platform will stop running.